Passengers flying into the United States from Nigeria, Yemen and other "countries of interest" will be subject to enhanced screening techniques, such as body scans and pat-downs, the Transportation Security Administration said Sunday.

Western embassies in Yemen locked up Sunday after fresh threats from al-Qaeda, and the White House expressed alarm at the terror group's expanded reach in the poor Arab nation where an offshoot apparently ordered the Christmas Day plot against a U.S. airliner.

President Obama laid blame Saturday on an al-Qaeda affiliate for a Christmas Day terrorist attack that has prompted a top-to-bottom review of how the nation's intelligence agencies failed to prevent the botched bombing aboard a Detroit-bound airliner.

President Barack Obama is reviewing reports from homeland security officials as his administration tries to determine what U.S. policy and personnel failures preceded the attempted Detroit jetliner bombing.

The terrorist watch lists at the center of what President Obama called the botched handling of intelligence on a plot to blow up an airliner on Christmas Day have been in the spotlight since the 9/11 terrorist attacks.

A "systemic failure" of the nation's intelligence gathering and analysis allowed a Nigerian man to board a flight to Detroit on Christmas Day in an alleged attempt to blow up an airliner, President Obama said Tuesday.

The alleged Christmas Day plot to blow up a Detroit-bound airliner further complicates President Obama's decision to close the Guantanamo Bay detention center and send some of the 198 terrorism suspects held there back to their own countries.